script for downloading a set of images on a page

img-download.js

(() => {
	const SELECTOR = '#container img';
	const NAME = 'prefix_{NUM}.png';

	const elCanvas = document.createElement('canvas');
	const ctx = elCanvas.getContext('2d');

	const a = document.createElement('a');

	function download(elImg, filename) {
		elCanvas.width = elImg.naturalWidth;
		elCanvas.height = elImg.naturalHeight;
		ctx.clearRect(0, 0, elCanvas.width, elCanvas.height);
		ctx.drawImage(elImg, 0, 0);

		a.href = elCanvas.toDataURL();
		a.download = filename;
		a.click();
	}

	document.querySelectorAll(SELECTOR).forEach(async (elImg, idx, arr) => {
		try {
			download(elImg, NAME.replace('{NUM}', idx.toString(10).padStart(arr.length.toString(10).length, '0')));
			return;
		} catch (e) {
			console.error(e);
		}
	});

  a.remove();
  elCanvas.remove();
})();